package cn.modernpoem.util;

/**
 * @author zhy
 */
public class EditDistance {
    public static int minDistance(String word1, String word2) {
        int[][] dp = new int[word1.length() + 1][word2.length() + 1];
        for (int i = 0; i < word1.length() + 1; i++) {
            dp[i][0] = i;
        }
        for (int i = 0; i < word2.length() + 1; i++) {
            dp[0][i] = i;
        }
        for (int i = 1; i < word1.length() + 1; i++) {
            for (int j = 1; j < word2.length() + 1; j++) {
                if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = 1 + Math.min(dp[i - 1][j - 1], Math.min(dp[i - 1][j], dp[i][j - 1]));
                }
            }
        }
        return dp[word1.length()][word2.length()];
    }

    public static String maxPrefixOf(String word1, String word2) {
        int length = Math.min(word1.length(), word2.length());
        for (int i = 0; i < length; i++) {
            if (word1.charAt(i) != word2.charAt(i)) {
                return word1.substring(0, i);
            }
        }
        return word1.substring(0, length);
    }
}
